You can also get and from the moment generating function. For the derivation of the moment generating function read this thread: http://www.mathhelpforum.com/math-he...tribution.html. If you haven't learnt about the moment generating function then forget I mentioned it.

You can also get and from the moment generating function. For the derivation of the moment generating function read this thread: http://www.mathhelpforum.com/math-he...tribution.html. If you haven't learnt about the moment generating function then forget I mentioned it.